fix paddle.static.load_inference_model api (#54833)

python/paddle/static/io.py

@@ -528,11 +528,18 @@ def save_inference_model(
         legacy_format=legacy_format,
     )
     save_to_file(model_path, program_bytes)
-    # serialize and save params
-    params_bytes = _serialize_persistables(program, executor)
-    # program may not contain any parameter and just compute operation
-    if params_bytes is not None:
-        save_to_file(params_path, params_bytes)
+
+    vars = list(filter(is_persistable, program.list_vars()))
+    if len(vars) > 0:
+        save_dirname = os.path.dirname(params_path)
+        params_filename = os.path.basename(params_path)
+        save_vars(
+            executor,
+            dirname=save_dirname,
+            main_program=program,
+            predicate=is_persistable,
+            filename=params_filename,
+        )
 
 
 @static_only
@@ -581,6 +588,7 @@ def deserialize_program(data):
     return program
 
 
+# NOTE(liuyuanle): Due to load from memory, deserialize_persistables does not support loading weights with file sizes exceeding 2GB.
 @static_only
 def deserialize_persistables(program, data, executor):
     """
@@ -797,16 +805,29 @@ def load_inference_model(path_prefix, executor, **kwargs):
 
     # load from memory
     if path_prefix is None:
-        _logger.warning("Load inference model from memory is deprecated.")
+        _logger.warning(
+            "Load inference model from memory is deprecated. Please specify path_prefix."
+        )
         model_filename = kwargs.get('model_filename', None)
         params_filename = kwargs.get('params_filename', None)
         if params_filename is None:
             raise ValueError(
                 "params_filename cannot be None when path_prefix is None."
             )
-        load_dirname = ''
         program_bytes = model_filename
-        params_bytes = params_filename
+        # deserialize bytes to program
+        program = deserialize_program(program_bytes)
+
+        vars = list(filter(is_persistable, program.list_vars()))
+        if len(vars) > 0:
+            load_vars(
+                executor,
+                # load from memory, dirname is None
+                dirname=None,
+                main_program=program,
+                predicate=is_persistable,
+                filename=params_filename,
+            )
     # load from file
     else:
         # check and norm path_prefix
@@ -841,24 +862,27 @@ def load_inference_model(path_prefix, executor, **kwargs):
                 if not os.path.exists(params_path):
                     params_path = os.path.join(path_prefix, params_filename)
             _logger.warning(
-                "The old way to load inference model is deprecated."
+                "The old way to load inference model is deprecated. Please specify path_prefix."
                 " model path: {}, params path: {}".format(
                     model_path, params_path
                 )
             )
         program_bytes = load_from_file(model_path)
-        load_dirname = os.path.dirname(params_path)
-        params_filename = os.path.basename(params_path)
-        # load params data
-        params_path = os.path.join(load_dirname, params_filename)
-        params_bytes = None
-        if os.path.exists(params_path):
-            params_bytes = load_from_file(params_path)
 
-    # deserialize bytes to program
-    program = deserialize_program(program_bytes)
-    # deserialize bytes to params
-    deserialize_persistables(program, params_bytes, executor)
+        # deserialize bytes to program
+        program = deserialize_program(program_bytes)
+
+        vars = list(filter(is_persistable, program.list_vars()))
+        if len(vars) > 0:
+            load_dirname = os.path.dirname(params_path)
+            params_filename = os.path.basename(params_path)
+            load_vars(
+                executor,
+                dirname=load_dirname,
+                main_program=program,
+                predicate=is_persistable,
+                filename=params_filename,
+            )
 
     feed_target_names = program.desc.get_feed_target_names()
     fetch_target_names = program.desc.get_fetch_target_names()
@@ -952,7 +976,7 @@ def save_vars(
     if dirname is None and filename is None:
         save_to_memory = True
 
-    main_program = paddle.static.io._get_valid_program(main_program)
+    main_program = _get_valid_program(main_program)
 
     if vars is None:
         return save_vars(